The prevalence of apple Valsa canker (AVC) poses a significant threat to the vitality of apple trees, jeopardizing the progress of the apple industry. Current strategies have proven inadequate in managing the disease effectively due to challenges such as extended duration and frequent relapses, especially low-adhesion vertical target. Herein, we introduce a pesticide-fertilizer synergistic alginate-based hydrogel (P&F-Gel) to enhance long-term pesticide retention and offer nutrient supplementation without labor-intensive practices. By sequentially spraying a suspension concentrate with sodium alginate (SA) as thickening agent, followed by a cross-linked fertilizer (CCF) dominated by Ca